you probably don't have that decoration mode turned off. Add this to
your .emacs file:

(semantic-load-enable-gaudy-code-helpers)

or turn on just the single item:

(require 'semantic-decorate-include)

It can be handy to see what state semantic is in sometimes.

I found that gaudy-code-helpers conflict with another addon of Emacs which is called tabbar (it's used to display a tab bar). So finally i used the latter method to make it work.

In the includes summary there're lots of include files listed, i'm not surprised at the amount, but i'm curious that what's the searching flow of semantic? Will semantic search the symbol in the order as same as the files are displayed? That's, if you see include summary like this:

a.cppa.hppiostream

And what you need is all in a.hpp, which of the following will semantic choose?

1. first search a.cpp, then a.hpp, then stop (since we've found the symbol)2. traverse all the files listed above, and finally stop.

I want to know the answer because I found it always takes too much time before getting the completions, while most of the time the infos for the completions can be found in the first several files.